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Chapter 1 : Exploring the Network
__TOC__ Objective Questions How do networks affect the way we interact, learn, work and play? How do networks support communication? What is a converged network? What are the four basic requirements of a reliable network? What are the uses of various network devices? How do the devices and topologies found in a LAN compare to those found in a WAN? What is the basic structure of the Internet? How do LANs and WANs connect to the Internet? What impact do BYOD, online collaboration, video and cloud computing have on a business network? How are networking technologies changing the home environment? What are some basic security threats and solutions to both small and large networks? Definitions Server: A host that transmits data. Client: A host that requests, receives and displays data. Peer-to-Peer: A network where hosts both transmit and receive data. Device: A physical termination of media and is any object that processes a request. Service: The non-physical software that makes use of the devices and media. Media/Medium: The physical connection between two devices and that is terminated at both devices. Physical topology diagrams: Identify the physical location of devices in a network. Logical topology diagrams: Identify the devices, ports and IP schemes. LAN: Local Area Network - Network over a small geographical area. WAN: Wide Area Network - Network over a large geographical area. MAN: Metropolitan Area Network - Network over a medium geographical area. SAN: Storage Area Network - Network designed to support file servers. WLAN: Wireless Local Area Network - Wireless network over a small geographical area. Internet: The largest network in the world. Literally "The network of networks" Intranet: A collection of interconnect LANs and WANs accessible from within a single organization. Extranet: A collection of interconnect LANs and WANs accessible from within a select group of organizations. Fault Tolerance: The ability of a network to provide unaffected service if a fault occurs. (Redundant connections). Scalability: The ability of a network to expand and provide service to new users and not affect existing users. Quality of Service (QoS): The ability of a network to prioritize types of communication to provide sufficient service to all rather than too good server to one and not enough service to another. Security: The ability of a network to protect the network from unauthorized access both through the software or the physical devices/media. Circuit-Switched: A network behavior in which once a session is set up it the resources used by the session (a circuit path) is not available until the session is disconnected. Packet-Switched: A network behavior in which data is broken up into packets and dynamically sent along the best circuit path at the time of sending. This makes dynamic use of redundant paths. Video Communication: Communicating through 2 way streaming video. Cloud Computing: Data stored and accessed on a remote server rather than locally. Labs 1.2.3.3 1.3.1.3 1.5.1.1 Chapter Notes 1.0 - Introduction The internet is gaining a life of it's own as it matures. It is beginning to be the source of new ideas rather than the meathod of implimentation for old ideas. The specifications for networks is now the diving board for concepts that imporve business, learning and play. Concept of the Internet: TBU 1.1 - Globally Connected 1.1.1 Networking Today Communication, interaction and community is very low on Maslow's Hierarchy and vitally important in our world today to supply the lower order needs. There is constant improvement on how humans communicate, from face-to-face interaction, writing, telephones and now digital. Data networks allow for instant global communication. This allows ideas and projects in business and education to be developed from people seperated geographically. Improvement in communications through networks allow total productive output of all involved; from the indivdual to the entire world. The development of the global network that is the internet has 3 existing stages and a future stage. Pre 2000s - Fixed Computing (The device is fixed and you must attend it) 2000s - Mobility/BYOD (The device is carried with you) 2010s - Internet of Things (Stage of Devices) Future - Internet of Everything (People, Places, Data, Devices) This future is begining with Google, Youtube, Facebook and Wikipedia. The amount of things (People, Places, Data, Devices) connected to the internet is doubling in increasingly shorter ammounts of time. However this increase in growth will platau when all exisitng infomation has been asimilated by the internet and the rate of new information on the internet will be similar to the rate that information is being produced. Mobile networking is a important area of improvement as it allows increasing quick access to data as well as decreased time between the creation of data (e.g. a news event or taking of a photo) and the sharing of the data on the internet. The use of instant data networks is begining to remove the impacts of physical and geographical limitations on business, education and play. The creation of global communities that transcend timezones or geographical location create a global 'Human Network'. Smaller, more indivdual networks can work under the banner of larger networks to create a place for people to find global communities relavant to indivual intrests and occupations. The global network is a force of improvement for edcuation; removing geographical and phsyical barriers to all education. Collaboration across vast distances allow for a total education without being present at the instiution conducting the class. Features such as virtual classrooms and messageboards allow for communication between students and instructors improve a student's learning a through human interaction. In addition, mobile and quick access to data such as textbooks, wikis, videos and text allows for a person to self-educate without the need for face-to-face interaction to recieve hard copies of information. Individual communication in the form of IRC improves the ability for indivuals to interact both in a geographical sense and a time sense. Instant and mobile communication is a function of the internet. Webblogs and podcasts allow people to share ideas with the world without needing to go through a large publishing company. P2P allows for files to be transfered between two individuals instentainously. This can be used for good, e.g. collabortation on music projects ect.., or it can be used for ill, e.g. illegally transfering someone else's intellectual property ect.... Almost all recreation has at least a small element of community and interaction. Even solo pursuits like painting or gardening benefit from the advice, experience and appreciation of others. The internet and networks in general allow for instant communication between thousands of people that enjoy the same recreation disregarding geographical barriers. Services such as online shopping, online gaming, and data networks on ships and planes allow people to access recreation anywhere at any time. 1.1.2 Providing Resources in a Network A network is at minimum two devices linked by a medium. At the core this is all a larger network is, a collection of two devices connected by a medium. However the functionality of a larger network is far greater than that of a lot of small networks. Networks can be found in the home, (e.g. connect computer and tablet to printer.) in small offices and large companies and multinational organizations. The largest network is the internet (literally meaning "The network of networks".). The internet is actually a connection of all of the smaller networks around the world bundled together by common protocols so everything on it can be accessed anywhere in the world. Every computer (also End Device or Host) connected to a network fall into one or both of two categories: a switch or a client. The category of a computer is determined by the software it is running. All hosts can both receive and transmit information. A client has the ability request and display information from a server. A server has the ability to process the requests of a client and to transmit the information requested by the client. Hosts can run multiple clients and servers simultaneously on the same device; however this causes problems in speed as one host is both receiving and transmitting. 1.2 - Lans, Wans and the Internet 1.2.1 Components of a Network There are three components of a network: devices, media and services. A network is at minimum two devices, one media and two services. A device is a physical termination of media and is any object that processes a request. (e.g. computer, switch, router, ect...) A media is the physical connection between two devices and is terminated at both devices. It can be both tangible (e.g. copper, fiber optic) or intangible (e.g. radio waves from Wi-Fi). A service is the non-physical software that makes use of the devices and media. This is the top 3 layers of the OSI model. (Application, Presentation, Session). A network's only function is to transfer data. The end result of all network use is to transfer data from one host to another. This may be direct across one media or it may go through a dozen devices and just as many media. Examples of end devices are computers, printers, scientific sensors and mobile devices. 1.3 - The Network as a Platform 1.4 - The Changing Network Environment 1.5 - Summary